钢液的精炼脱氮方法

本发明所涉及钢液精炼脱氮装置由真空系统，直流脉冲电源，工作气体和辉光等离子发生系统组成。依靠直流脉冲电场在钢液上方形成氩-氢混合气体的辉光等离子体，钢液中的氮与辉光等离子体作用，逸出离子态的氮并与工作气体反应，最后形成氮气和氨气并由真空系统抽出装置从而达到脱氮的目的。     

射频辉光放电发射光谱在深度分析有效信息量方面的改进

评述了射频辉光放电发射光谱中的两种新的测量方法：调幅技术和偏置电流导电技术。这两种方法在分析薄膜试样时非常有效。应用调幅技术时，辉光放电电压以低频进行调制，在发射信号周期性变化的同时，溅射率降低。尽管随脉冲数的减少发射强度降低，但发射强度能用选频放大器选择性地进行检测，从而能获得较好的信噪比。在偏置电流导电技术中，直流偏置电流被导入由低通滤波器和负载电阻组成的辉光放电灯电路中，偏置电流将大量电子引入等离子体中，从而导致等离子体区域发射强度的增强，而同时由于偏置电流的减少而使得溅射率降低。这两种技术有利于改进辉光放电发射光谱的深度信息分析。     

氩直流辉光等离子体钢液脱氮的研究

用25 kg真空感应炉对0.02%C钢液进行氩直流(DC)辉光等离子体条件的脱氮实验,研究了氩辉光等离子体对钢液脱氮动力学的影响。结果表明,氩辉光等离子体钢液脱氮速度和脱氮效果明显优于真空钢液脱氮,当钢液氧含量为180×10^-6,在氩辉光等离子体下钢液中氮含量可降至9×10^-6。氩辉光等离子体对钢液的脱氮效果体现在界面化学反应上,提供了加速脱氮反应的动力学条件。     

应用于固体样品直接分析的射频辉光光谱中等离子体空间解析的初步研究

设计了一种新的实验设备用于研究发射光谱的射频辉光中原子和离子的空间分布。通过测量沿等离子体羽流的不同原子和离子的发射强度来研究发生在等离子体内部的激发/离子化过程。该报导对辉光源与质谱联用的优化有较大意义,如离子提取的最佳位置。初步研究了连续和脉冲射频辉光光谱中等离子体的空间解析,尤其对影响发射信号的输入功率、压强及占空比等参数进行了评价。     

高纯材料中痕量元素分析的发展趋势

本文综述了我国高纯材料中痕量元素分析的发展趋势，开展对世界三家公司生产研制的先进分析仪器，电感耦合等离子体质谱，辉光放电质谱进行调研，对讨论了一些问题。     

Ka波段PHEMT MIMIC VCO设计

给出了Ka波段PHEMT MIMIC VCO设计过程，根据直流特性曲线确定直流工作点，得到对应的S参数，再转化为Z参数，计算出输入输出谐振回路和输出电路的阻抗，用Agilent ADS软件进行了仿真，振荡中心频率33．14GHz，用PHEMT管作为变容管，调谐带宽为200MHz。     

直流电弧所在电网线路非稳态分析及功率的合理分配

由电弧启动到正常工作这段时间，电网线路的电流电压波动性较大，往往给电路其它各元件造成强烈的冲击。据此，利用电弧伏安特性曲线对电网电路非稳态过程进行了分析，并理论推导了既适合电路稳定性要求又能保证电弧具有理想输出功率的最佳电网阻抗匹配值，现实上对正确使用直流电弧具有重要意义。     

直流辉光放电质谱法测定高纯氧化镧中25种杂质元素

利用铜粉作为导电介质, 与氧化镧粉末混合均匀, 压片, 采用直流辉光放电质谱法(dc-GDMS)测定了高纯氧化镧粉末中的部分杂质元素含量。考察了辉光放电条件, 如放电电流、放电气体流量、离子源温度以及压片条件, 如两种粉末的混合比例、压片机压力等因素对放电稳定性以及灵敏度的影响, 优化了实验条件;尝试了将镧, 氧和铜的总信号归一化进行计算的方法, 用差减法计算了高纯氧化镧粉末中的杂质元素含量。将铜粉作为试剂空白, 连续测定11次, 统计各待测元素检出限为0.005~0.34 μg/g;对高纯氧化镧粉末样品独立测定6次, 测定结果与电感耦合等离子体质谱法基本吻合, 相对标准偏差在20%以内。     

高纯锌的制备及检测技术研究进展

高纯锌是制备化合物半导体材料、精密铸件、还原剂、高纯金属盐和高纯金属有机化合物的重要材料。高纯锌的重要应用依赖于制备和检测技术的发展。围绕超高纯锌产品和高纯锌化学分析两个行业标准，重点介绍了高纯锌的电解法、真空蒸馏法和区域熔炼法等制备方法以及辉光放电质谱法(GD-MS)、电感耦合等离子体质谱法(ICP-MS)、极谱法、氢化物发生-原子荧光光谱法(HG-AFS)、电感耦合等离子体原子发射光谱法(ICP-AES)、原子吸收光谱法(AAS)、分光光度法等检测方法。高纯锌的制备需要逐级提纯，包括电解法初级提纯、真空蒸馏法提纯、区域熔炼精炼和超纯化。高纯锌中的杂质元素检测主要采用辉光放电质谱法和电感耦合等离子体质谱法，并辅以极谱法、氢化物发生-原子荧光光谱法、电感耦合等离子体原子发射光谱法等方法作为验证手段和补充。文章可以为高纯锌制备和检测方法的研究者提供相关借鉴和指导。高纯锌制备和检测技术的发展也促进了材料应用领域的拓展，目前高纯锌越来越多在电子信息、生物医药等高新技术领域得到应用。     

直流脉冲辉光等离子体控制电路及其灭弧效果分析

对等离子体氢还原金属氧化物实验中设计的控制电路进行了介绍,对控制电路实际灭弧功能进行了测试,分析了放电过程中引起弧光放电的原因,指出维持稳定辉光放电需要采取的措施.     

Nitrogen Removal from Molten Steel under Argon DC Glow Plasma

Under argon DC glow plasma, the nitrogen removal from molten steel was studied. The experimental result showed that nitrogen mass percent could be reduced to 0. 000 8 %. The change of polarity had no impact on nitrogen removal when the nitrogen mass percent was low. The mechanism of denitrogenation of molten steel under argon DC glow plasma was discussed.     

高流速高分辨辉光放电质谱法测定粉末高温合金中26种微量和痕量元素

准确测定粉末高温合金中微量及痕量元素,对粉末高温合金的生产、应用具有重要意义。将样品在放电电流40～45 mA,放电电压1 100～1 200 V,氩气流速400～450 mL/min下进行辉光放电激发,选择合适的同位素和分辨率以消除质谱干扰,使用基体匹配的内控标准样品和标准物质校准各待测元素的相对灵敏度因子(RSF),实现了高流速高分辨辉光放电质谱法(GDMS)对粉末高温合金中硼、钠、镁等26种微量及痕量元素的测定。采用实验方法对粉末高温合金内控样品中26种微量及痕量元素进行测定,各待测元素的测定值与参考值基本一致,测定结果的RSD(n=6)在0.9%～15.4%之间。采用实验方法对粉末高温合金样品进行测定,测定结果分别与电感耦合等离子体原子发射光谱法(ICP-AES)测定硼、铁和锆,高频感应燃烧红外吸收法测定硫,原子荧光光谱法测定硒,高分辨电感耦合等离子体质谱法(HR-ICP-MS)测定其余元素(钠、镁、硅、磷、钙、钒、锰、铜、镓、砷、银、锡、锑、碲、镧、铈、铪、钽、铊、铅和铋)的结果保持一致,测定结果的RSD(n=6)在0.2%～26.6%之间。     

高流速高分辨辉光放电质谱法测定粉末高温合金中26种微量和痕量元素

准确测定粉末高温合金中微量及痕量元素,对粉末高温合金的生产、应用具有重要意义。将样品在放电电流40～45 mA,放电电压1 100～1 200 V,氩气流速400～450 mL/min下进行辉光放电激发,选择合适的同位素和分辨率以消除质谱干扰,使用基体匹配的内控标准样品和标准物质校准各待测元素的相对灵敏度因子(RSF),实现了高流速高分辨辉光放电质谱法(GDMS)对粉末高温合金中硼、钠、镁等26种微量及痕量元素的测定。采用实验方法对粉末高温合金内控样品中26种微量及痕量元素进行测定,各待测元素的测定值与参考值基本一致,测定结果的RSD(n=6)在0.9%～15.4%之间。采用实验方法对粉末高温合金样品进行测定,测定结果分别与电感耦合等离子体原子发射光谱法(ICP-AES)测定硼、铁和锆,高频感应燃烧红外吸收法测定硫,原子荧光光谱法测定硒,高分辨电感耦合等离子体质谱法(HR-ICP-MS)测定其余元素(钠、镁、硅、磷、钙、钒、锰、铜、镓、砷、银、锡、锑、碲、镧、铈、铪、钽、铊、铅和铋)的结果保持一致,测定结果的RSD(n=6)在0.2%～26.6%之间。     

Effect of surface modification of high-density polyethylene by direct current and radio frequency glow discharge on wetting and adhesion characteristics

The present investigation aims to optimize the process parameters of Direct Current (DC) and Radio Frequency (RF) glow discharge treatment through air in terms of discharge power and time of exposure for the surface modification of high-density polyethylene (HDPE) sheet, for attaining best adhesive joint of the polymer to mild steel. In order to estimate the extent of surface modification, the surface energies of the polymer surfaces exposed to glow discharge have been determined by measuring contact angles using two standard test liquids of known surface energies. It is observed that at a given power level of DC glow discharge, surface energy and its polar component increase with increasing exposure time, attaining a maximum and then decreasing. In the case of RF glow discharge, surface energy and its polar component increase with increasing exposure time and then saturate. Surface modification by DC glow discharge increases the surface energy of HDPE relatively more at a lower power compared to that observed for RF glow discharge. The dispersion component of surface energy remains almost unaffected. The surfaces have also been studied by electron spectroscopy for chemical analysis (ESCA) and energy-dispersive spectra (EDS). A significant oxygen peak is observed for surface-modified polymer as detected by ESCA and EDS. Lap shear tensile test of an adhesive (Araldite AY 105) joint of HDPE with mild steel has been carried out in optimizing the parameters of DC and RF glow discharge for maximum joint strength. When HDPE is exposed to DC glow discharge, improvement of adhesive joint strength of HDPE to mild steel is found to be by a factor more than 7. On the other hand, when HDPE is exposed to RF glow discharge, results in improvement of adhesive joint strength of HDPE to mild steel by a factor nearer to 7 are found. Thus, DC glow discharge is more capable for increasing wetting and adhesion characteristics of the polymer.     

Nitrogen transfer into plasma heated steel melts as a function of arc polarity

Heating liquid steel in the tundish with argon stabilized plasma arcs is one example of the increasing importance of mobile and inert heating systems in metallurgy. Unwanted nitrogen pick-up caused by infiltrated air, and possibly aggravated by the activating effect of plasma, should be minimized by selecting the optimum current mode and torch polarity. With this aim in mind, the nitrogen transfer kinetics have been investigated on 150-kg low carbon steel melts at different nitrogen partial pressures as a function of arc polarity. The experimental plasma plant was equipped with a 2000-A torch, housing a thoria stabilized tungsten electrode, and a counter electrode located at the bottom of the crucible. The torch could be operated with DC of either polarity or with AC. Kinetic models of nitrogen transfer have been developed, which show good agreement with experimental results. Arc polarity has a significant effect both on the rate of nitrogen pick-up in the arc area (pumping effect) and on the mass transport in the melt (stirring effect). Of all configurations tested, the torch as cathode is the most suitable arc configuration for inert heating, since the particularly active N⁺ ions in the plasma are repelled by the melt surface. Furthermore, the relatively strong stirring effect of the plasma jet leads to the highest heat transfer efficiency. On the other hand, where controlled nitrogen pick-up is required, the highest nitrogen transfer rates are obtained with the torch poled as anode.     

Plasma Nitriding of 722M24 Steel with Pure Lanthanum, Cerium and Neodymium as Sputter Sources

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Variation of Lap Shear Tensile Strength of Polycarbonate–Mild Steel Adhesive Joints with DC Glow Discharge Modified Polycarbonate

It has been observed that the wettability/surface energy of polycarbonate (PC) changes with the variation in process parameters, such as discharge power and time of exposure of DC glow discharge. The wettability of the PC surface has been measured by the contact angle measurements of two test liquids, such as water and formamide, by the sessile drop method. The lap shear tensile strength (LSTS) of PC to the mild steel (MS) adhesive joint has been measured with both the as-received polymer and those exposed under DC glow discharge. An appreciable increase in the LSTS has been attained for samples treated under DC glow discharge at a lower power level and also at a short exposure time at higher power. This increase in LSTS is attributed to increased polar surface energy with increasing power and time of exposure. After a certain level of surface modification of the PC, the strength of the adhesive joint deteriorates, while the total surface energy and its polar component may increase continuously. The subsurface damage taking place particularly at long exposure times and at higher power may lead to deterioration of LSTS in spite of a strong interface between the polymer and the adhesive. In such a case, the joint is observed to fracture not across the interface but through the subsurface. The optimum exposure limits the subsurface damage while creating a strong interface.     

粉末冶金高致密化成形技术的新进展

本文针对粉末冶金行业近十年来出现的提高制品致密化的新途径新方法, 简要介绍了其中的温压技术,流动温压技术、模壁润滑技术、高速压制技术、动力磁性压制技术、爆炸压制技术、放电等离子烧结技术的原理、特点、发展和应用情况。指出发展粉末冶金高效高致密化成形技术是粉末冶金的发展方向和研究重点, 产品致密化程度的提高将大大促进性能的改进。粉末冶金新技术、新工艺、新材料的不断出现, 必将促进高技术产业的快速发展, 也必将带给材料工程和制造技术以光明的前景。     

等离子冶金理论与进展

综述了等离子冶金的理论与进展,着重等离子温度、射流速度及穿透深度计算,分析等离子在金属制备过程中的新应用,并展望其未来